Complex sentence: When World War I broke in 1914, he attempted to obtain a commission in the London Scottish Regiment, but was instead commissioned into the Royal Army Service Corps and was posted to a ration depot at Suez, due to the high standard of his French.
Split into simpler sentences: When World War I broke in 1914, he attempted to obtain a commission in the London Scottish Regiment, but was instead commissioned into the Royal Army Service Corps. He was posted to a ration depot at Suez, due to the high standard of his French.