The Manchester City midfielder, 31, is currently recovering from the hamstring injury that he picked up towards the end of the Premier League season.
While admitting that Toure is "responding" to rehabilitation, Lamouchi is not sure when he will be back to full fitness.
"He ended the season with difficulties," Lamouchi told Jeune Afrique. "He is yet to fully train with the group but he's currently responding to a healing protocol.
"We will do our best to make him fit to play against Japan in our opener. He might start or come in as a substitute. I can't really tell for now."
Ivory Coast take on Japan in their opening fixture of the World Cup on June 15.