Arnold was born in Wolverhampton in 1897, the son of William J. and Lavinia Favill. In 1901 he was living with his parents at 28 Temple Street, Wolverhampton, with brothers Frederick W. and Robert V., sisters Lavinia and Florrie, and boarders Richard and Sarah Rowlands. His father died later that year. By 1911 he was living with his widowed mother at 33 Queen Street, alongside his sister Elizabeth and brothers L. William, Robert V. and Charles S.
Arnold joined the South Staffordshire Regiment and became a Lance Corporal in the 2/6th Battalion (number 240895). He was killed in action in France on 21 March 1918, and appears listed on the Arras Memorial. He is commemorated in the Lady Chapel of St Peter’s Church, as well as on the war memorial of St John’s Church.