Not first use ever, as the term originated on DataLounge, merely first use in the Times, which has lied about us for decades: “With the notable exception of Christopher Isherwood, there were few benevolent eldergays in the literary scene.” (I did a database search to be sure.)
Apparent first use of “eldergay”
The foregoing posting appeared on Joe Clark’s personal Weblog on 2018.09.03 11:28. This presentation was designed for printing and omits components that make sense only onscreen. The permanent link is: https://blog.fawny.org/2018/09/03/timeseldergay/