Here let me introduce a new Wodehouse investigation.

The author is Norman Thomas Philip Murphy 1933 -- 2016.

According to his obituary in The Telegraph,
Murphy, a Lieutenant-Colonel, was employed by the Ministry of Defence in Whitehall
when he began 40 minutes of his hourly break in his workday,
looking in the British Library for Wodehouse's origins.
Several published books would result.

There are two volumes in Murphy's "Wodehouse Handbook."
I have yet to pull these up online; they are quoted online though.
Murphy confirms that the Harry Lauder recording is dated 1907
with "the interpolation after the second verse,
when he tells the audience to keep quiet because his love is
'coming -- she's coming -- she's coming --' and then
THE LINE."