I’ve written about this song elsewhere. It sounds very sad, doesn’t it? But if you take the lyrics at face value, it’s perfectly benign.
On a Sunday morn,
Sat a maid forlorn,
With her sweetheart by her side;
Through the window pane,
She looked at the rain
. . . and so on until you get to the “Ah-ha!” of the chorus:
“Wait till the sun shines, Nellie,
When the clouds go drifting by.
We will be happy, Nellie,
Don’t you sigh!
Down Lover’s Lane we’ll wander,
Sweethearts you and I.
Pause for all four members of the barbershop quartet to indulge in some fancy vocals . . .
Wait till the sun shines, Nellie,
By and by!”