I can't seem to find any conclusive data that Sasuke is Lightning based. True all his recent jutsu's are based on lightning and Kakashi said, "He is the same type as me", but also remember he learn how to use Fire based jutsus when he was 8?! I think unless Fire was his type he couldn't have done the jutsu just cause he knew the seals.
Also he might be using lightning to make ppl think he is lightning base so when someone uses wind against him he lets them know he really is fire and just help him make his jutsu stronger.