Bordeaux back in League Cup final
The Ligue 1 leaders will meet Olympique Marseille on March 27 at the Stade de France. No club have ever retained the title.
Lorient centre back Laurent Koscielny turned from hero to villain in the first half.
He first benefited from a scramble in front of the goal to fire home the opener from close range.
He was sent off a few minutes later for a challenge on Marouane Chamakh in the box although television replays seemed to show he did not touch the Bordeaux striker.
Wendel calmly converted from the spot despite the Lorient players' protest.
Chamakh then put Bordeaux in front just before the half hour with a powerful header.
Wendel scored a double with a splendid left-footed free-kick and substitute Yoan Gouffran added a fourth in the last 10 minutes to put Bordeaux's victory beyond doubt.