As I recall, this tune was written originally as a tune without lyrics, having been composed by Dan Alex MacDonald circa 1917. The theme of the tune reflected the emotional struggle of a world at war. I'm unsure who wrote the words or when. George Seto... if you're listening, can you help straighten us out on this one?
For the enjoyment of those not familiar with this air, here is my midi.
It's interesting that you refer to the lyrics in French, for the original lyrics were in Gaelic.