As best I can tell, the question didn't appear until 1992. It's possible that it was asked in the Voter News Service polls that were conducted during the mid-terms between 1994-2002 (and maybe even before that, if they provided them then), but you need a Roper Center membership in order to access those. Remarkably, or perhaps unremarkably, the gay vote has been relatively static for the past 20-something years.
1992: 72% Clinton
1996: 66% Clinton
2000: 71% Gore
2004: 77% Kerry
2006: 75% Democratic
2008: 70% Obama
2010: 69% Democratic
2012: 77% Obama
2014: 76% Democratic
Temporarily racist gays!? 
Source: 1992 ( Page 8 )
Source: 1996
Source: 2000
Source: 2004-2012
Source: 2014
Kerry probably overperformed due to Bush's support of the Federal Marriage Amendment and the gay marriage ban referenda in several states that year.
