The information below is from Arthur's Defence Force Personnel Record, from Archives NZ.
On 18 March 1913, Arthur was promoted to the rank of Second Lieutenant (on probabtion) in the Territorial Force, No. 5 Company, South Island Battalion, Post & Telegraph Corps. His rank at the time was Sergeant, giving his date of birth as 3 February 1884 and occupation as Telegraphist. He had passed the Sergeants' examination on 25 July 1906. This was duly Gazetted on 6 November 1913.
On 23 October 1916, Arthur applied to "Be placed on the Reserve of Officers". The application form cited his length of service as 4 nyears 7 months, although this was amended to 3 years 7 months. This application was accompanied by a letter from V. Dunne (Captain, Staff Officer), in which it is stated that Arthur "is so taken up with his duties as secretary to the Hon. the Minister for Agriculture as to be unable to give any time to the training of the No. 5 Company Post and telegraph Engineers, Invercargill, of which Company he is in charge. The Corps is suffering through several similar cases which I am endeavouring to rectify."
In a letter dated 17 November 1916, Douglas Bryan, Captain, Assistant Military Secretary, noted that Arthur "was appointed 2nd Lieutenant (on probation) to the New Zealand Post and Telegraph Corps (South Island Battalion as from 18th March 1913.
There is no record at Headquarters that this probationary Officer has passed the prescribed examination as laid down in Para. 89 General Regulations, and his appointment under that regulation should have lapsed." The lapsing of this appointment was duly Gazetted on 14 December 1916.