The 24-year-old, who made 32 Ligue 1 appearances for Christian Gourcuff's side last season and scored three goals, is now tied to the club until 2017 and expressed his delight with the news.
"It is a sign of confidence on the part of the club. I'm very happy," Kone told the club's official website.
"Since I arrived at Lorient, I have progressed a lot. This gives me three more years to develop in contact with Christian Gourcuff.
"Now it's up to me to work hard, have a good season and repay the confidence the club have shown in me."
Gourcuff added: "It's pleasing, the club's wish was to extend his contract.
"Lamine has progressed a lot since he has been here. He was an important player last season and still has plenty more room to develop. It's very good for Lorient."
The Paris-born player was signed from Chateauroux in 2010 following five seasons with the Ligue 2 side.