Monaco are only one point ahead of Brest, who moved up to second place after rallying to win 2-1 at Reims on Sunday. Midfielder Pierre Lees-Melou grabbed the winner in the 56th minute.
Balogun scored in the 69th after Aleksandr Golovin picked him out in the penalty area and he held off a defender before finishing with his left foot.
The 22-year-old Balogun joined Monaco from Premier League side Arsenal for 40 million euros ($A66 million), after scoring 21 league goals in the first division last season on loan to Reims. But Romain Faivre levelled for Lorient in the seventh minute of added time.
After Benin striker Aiyegun Tosin fired Lorient ahead in the second minute with his first goal for the club, Golovin equalised in the 17th with midfielder Youssouf Fofana setting him up.
Former Manchester City defender Benjamin Mendy came on for Lorient in the 70th. The left back, who won the World Cup with France in 2018, signed a two-year deal in July, after he was found not guilty of raping a woman and the attempted rape of another. He had not played for City since 2021.
Marseille remain unbeaten but failed to pressure Monaco after drawing 0-0 at home to Toulouse, for whom Socceroos midfielder Denis Genreau played 72 minutes. The result leaves Marseille in fourth place on goal difference behind third-placed Nice and one point adrift of Brest.
Elsewhere, Nigeria winger Moses Simon scored the winner as Nantes won 1-0 at Clermont and Strasbourg fought back from 2-0 down to draw 2-2 with Montpellier.
In the late game, struggling Lyon drew 0-0 with promoted Le Havre in Lyon's first match since parting ways with coach Laurent Blanc. The seven-time French champions Lyon have two points from five games and are 16th in the 18-team league.
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