If you go back to the original version of ARE YOU LONESOME TONIGHT? and sing slowly it with the original verse (which no-one ever sings), you'll find it's a delightful sentimental waltz from the 1920s. The only version of the complete thing that I know of on record is by Leon Redbone. Well worth a listen.

Performing it live is fun, because no-one ever knows what the verse is leading into and, when you launch into the chorus, you can almost hear them thinking, "Oh - that's what it is!"