Interesting EH-related items will occasionally show up on ebay, such as this invitation to an art auction at the Julien Levy Gallery. Listing first under the heading "entertainment" is "Elsie Houston: Brazilian Strip Tsi Tsi Dance." (I know nothing about this particular act). Listed second, her friend, Sam Barlow, doing "Pocket Book Whittling." My guess would be 1938, when she was still breaking in to the NY social scene. [UPDATE: 1937]