Source: August 1918 War Diary TOS.
NOTE: this soldier’s service records shows service with the 19th Battalion and that research does not find any other soldier than this one as being the most likely candidate. Google search finds some images and bio. It is possible that the War Diary entry of August 13, 1918 is referring to Lieutenant Henry Rothewell Gerrard who joined the Battalion in December, 1916. More research will need to be done.
War Diary of the 18th Battalion CEF 