Delivery just happened of my order of a second-hand copy of
the Allan Nevins biography of Henry White the 'diplomatist'.
It's over five hundred pages in length.
I could not resist looking at a few chapters.

This whole business about the Elm Court stately home,
in Lenox, Massachusetts, hosting chats before the Paris Peace Conference,
seems predicated upon the person of Henry White,
who married a Vanderbilt heiress.

The Sloane family, who had the Elm Court property built in the first place,
moved in the social circles with Vanderbilts and so on
(they were Vanderbilts who married into the Sloane family);
and Henry White, with his wife Daisy, also socialized at that top echelon.
There is a statement by biographer Nevins that
Mr. and Mrs. Henry White, and Mr. and Mrs. Sloane,
were indeed on excellent terms with each other and
that the ladies/wives were particularly dear friends.

Then Mrs. Sloane became a widow, and Mr. White, a widower.
Both were senior citizens when they got married to each other ...
except that the marriage actually happened in 1920,
after Henry White had completed his last diplomatic assignment
as part of the American delegation to the Paris Peace Conference.

In those days, when there was to be a summit/conference in Paris,
people did not board airplanes to get there.
They boarded ships, if going overseas, at any rate.

Henry White, along with the US President and the American delegates,
boarded ship on 8 December 2018, shortly after the Armistice.
He would not return to the United States for nearly twelve months,
although others of the Americans -- notably, President Woodrow Wilson --
would go back and forth across the Atlantic in support of the Treaty of Versailles and the League of Nations.

So if these "Elm Court Talks", as the local myth has it,
required the presence of Ambassador Henry White,
then they would have to have taken place in Lenox
BEFORE the 8th of December in 2018 ...