I can confirm that the versions posted by Stewie and Guest Phillip above are identical to the lyrics recorded by James Taylor in about 1972-73.

I'd say there's a good chance that Taylor's version inspired the other two recordings quoted which seem to have come out shortly after this.

The "arm in arm along the road" version, called "The Nightengale" was also widely sung by Irish "Ballad Groups" in the 1960s & 70s, although I haven't heard it sung much since then.