“Loch Lomond” is a nineteenth-century imitation of Scottish folk-song and therefore about as inauthentic as a pice of music can be, if you care about authenticity, which I most assuredly do not. Yes, it walks right up to the edge of schlock; yes, it has a thousand luridly sentimental associations, even for those of us who aren’t Scots.
It is also one of the loveliest melodies I’ve ever heard, something that Ralph Vaughan Williams discerned when he gave it this magnificent arrangement — indeed, just this one song constitutes a kind of master-class in vocal arrangement, for those who are willing to hear it. Consider the keening of the tenors, the tragic fundament of the basses, the lovely exchange of responsibilities in the last verse as the lead singer gets the chorus.
Call it inauthentic, call it sentimental, whatever. It’s magnificent and you know it.