Jean Louis Garcia's side went into tonight's second leg with a 2-1 lead following their victory at the Stade de l'Aube earlier this week, and they held on for a goalless draw in the away tie to confirm their place back in the top flight.
Lorient picked up just two points from the last 12 on offer in the regular season to finish one point adrift of safety in Ligue 1, but they could have levelled things up on aggregate as early as the fourth minute this evening when Benjamin Moukandjo struck the post with a firm header in the opening exchanges.
Troyes may have felt that they were worthy of promotion having only missed out on the automatic route via goal difference following a thrilling final day of Ligue 2 action which saw six teams still in with a chance of winning the title.
Only a last-gasp Amiens goal knocked Troyes out of the top two, but they would not be denied and held on to their first-leg lead at the Stade Yves Allainmat le Moustoir.
Lorient were unable to work their way back into the tie having lost the first leg to a stoppage-time goal, condemning them to relegation from Ligue 1 after an 11-year stay in the top flight.