Sloan Privat's first-half goal allowed Sochaux to register what could prove to be a vital win in their battle to avoid relegation from Ligue 1.
The striker scored with 30 minutes on the clock and, with Lorient unable to respond, Sochaux moved out of the drop zone and on to 37 points.
They did so by leapfrogging Nancy - who are fourth bottom and play tomorrow - and Evian, who lost at Troyes.
With three games to go they have no margin for error and tonight's victory could prove to be a telling one, albeit surprising, as Lorient are comfortable in the top half.
That showed as the visitors impressed early on, with Jeremie Aliadiere skipping past Carlao and Cedric Kante before cracking a strike against the post.
Former Arsenal man Aliadiere continued to pour forward and his cross, which was not cleared, then fell to Yann Jouffre but his volley was saved by Simon Pouplin.
Sochaux had shown nothing at that point, but went ahead with their first attack.
Ryad Boudebouz played Giovanni Sio in and his cross was met by Privat, who beat Benjamin Lecomte with his seventh of the season.
Lorient returned to the front foot after that - Jouffre denied by Pouplin again - and the one-way traffic continued after the break.
Aliadiere was frustrated by Pouplin and the goalkeeper, enjoying one of the nights of his life, then produced a brilliant, point-blank stop to keep out Maxime Baca's volley.
Realising they could not simply hold what they had, Sochaux attacked and Vincent Nogueira and Boudebouz drew a double save from Lecomte, before the normal order was resumed and Pouplin kept out Jouffre.
That would be the end of the action, though, as Sochaux held out.