|Senator||Faculty of Catholic Theology||1949/50|
|Dean||Faculty of Catholic Theology||1950/51|
|Senator||Faculty of Catholic Theology||1952/53|
|Senator||Faculty of Catholic Theology||1953/54|
|Senator||Faculty of Catholic Theology||1954/55|
|Dean||Faculty of Catholic Theology||1955/56|
|Senator||Faculty of Catholic Theology||1959/60-1960/61|
|Rector||Faculty of Catholic Theology||1961/62|
Arnold attended the Sperlgasse secondary school in Vienna’s second district until 1912 and then studied theology at the University of Vienna. In 1916, he was ordained as a priest in the Stephansdom (St. Stephen’s cathedral in Vienna). Subsequently he worked in pastoral care and as a teacher of religious education at the school for the deaf-mute as well as at the orphanage in Speising from September 1916 until July 1917. Following this, he went to Hainburg as an assistant priest (August 1917-August 1st, 1918), where he was active in various associations and at the Christian union. On September 1st, 1918, he was assigned to the administration of the Caritas association in Vienna as the speaker for child and youth welfare. He rendered great services in connection with the youth association "Frohe Kindheit" (Happy Childhood) and was co-founder of the Sisterhood of the Holy Agnes. Later he also took over as organizational head of the Caritas association (until August 1st, 1930). As of September 1st, 1918 (until January 1st, 1939), he also worked as an assistant priest in the parish of Maria Geburt (Birth of Mary) in Vienna’s 3rd district. In 1928 he obtained his doctorate in theology, and in 1930 in Canon and Civil law. In that same year (1930), Arnold was voted into the state parliament of Vienna as well as the municipal council. He held these positions until February 1934. A short time afterwards, in 1935, he habilitated in Canon law (by decree of the Federal President from April 16th, 1935) with the paper “Das Diözesanrecht nach den Schriften Hinkmars von Reims”. This was followed by an appointment to the diocesan court as an archiepiscopal judge as of October 9th, 1936, a position he held until March 26th, 1946, and therefore also during the Nazi-era.
After Austria’s “Anschluss” to the German Reich Arnold’s venia legendi was “suspended until further notice” as of April 22nd, 1938, and was revoked completely on July 6th. This disciplinary measure can be explained in light of the personnel-wise and institutional weakening of Catholic theology after the “Anschluss”: The faculty in Vienna was the only one of four that remained intact. Arnold’s work in Vienna’s state parliament until 1934 presumably also was a reason.
After the end of the war, on June 6th, 1945, the Staatsamt für Volksaufklärung (government office for public enlightenment) reinstated Arnold’s venia and entrusted him with substituting the chair for Canon law on September 30th, 1945. Beginning in 1946, he became associated professor for Canon law and a member of the Staatsprüfungskommission (commission for state exams) for legal history exams, and a year later he became full professor for Canon law. He held the chair until his death in 1963. Apart from this, Arnold also held several other positions at the University of Vienna: For more than a decade he was senator of the Catholic-theological faculty in the academic senate (1949/50, 1952/53-1854/55 and 1959/60-1960/61), acted as dean of the Catholic-theological faculty in the academic years of 1950/51 and 1955/56, in the respective years afterwards as vice dean and 1960/61 as rector and in the following year vice rector. He was awarded the Rektorserinnerungszeichen (rector remembrance award) in 1962. In 1963 he was sworn into office as first presiding judge and “now also was to bring matters of morals as well as those of justice before his forum”. A short time before his death, on April 5th, 1963, the Catholic-theological faculty had requested an honorary year for Arnold, which was approved by the ministry on May 10th, 1963. In his last year of life, he was made a papal house prelate, while also receiving the Grand Decoration of Honor for Services to the Republic of Austria in Silver. Furthermore, he was also bearer of the Knight’s Cross of the Austrian Decoration of Honor.
Arnold’s research focused on the fields of diocesan law according to texts by Hinkmar von Reims as well as on Catholic marital law.