According to detailed info I've located, the Dream Lights began Nov. 4 in 2011.
That would mean that the D-Lights first two nights were actually during the last two dates of Daylight Saving Time, so the "Cinderella's Holiday Wish" lighting ceremony would have been performed at 7:15PM EDT on those first two nights. On the rest of the D-Lights evenings, that ceremony would have begun at 6:15PM Eastern
Standard Time.
In July of this year, Disney posted on its website that the Dream Lights would begin on Nov. 2 of 2012. But, that date seems unlikely. (The Disney website is infamous for erroneous early postings.)
It wouldn't make sense that they would start the D-Lights on the last night of
MNSSHP.
The castle has much "spookier" lighting during the Halloween Party, and the D-Lights
would be out-of-place for that.
That "Nov. 2" start date info has since been removed from the Disney site.
The most consistent info that I can find for 2012 looks like a Nov. 5 (Mon.) start-date, which also happens to be the first night of dropping back to "Standard Time" in 2012.