His older brother Nathaniel, who is at Watford, is an England intentional.
Trevoh, who is 1.90 metres tall, spent the last two years playing in the English championship, first on loan at Ipswich and last season on loan at Huddersfield.
“Trevoh is a young player with a lot of experience,” said Lorient coach Christophe Pelissier.
“He has built up a character that allows him to play at the highest level and to fight to stay there. A versatile player, since he can also play in central defence, Trevoh has an athletic profile that complements our squad.”