Marc Marquez and Dani Pedrosa have finished one-two in the past two events at Austin and Jerez, the latter result coming despite confidence that Jerez would favour Yamaha.
Lorenzo, who lost second to Marquez following a last-corner clash, says Yamaha was specifically affected by high ambient temperatures at the Spanish track.
He feels the subsequent day of testing, during which he racked up the most laps of any rider, allowed Yamaha to get on top of the areas it was losing ground to Honda.
"I arrive at Le Mans with a lot of motivation after the Jerez results," he said.
"Perhaps we expected better there but we struggled much more than we expected because of the extreme heat on the track.
"Fortunately we worked a lot on the test day afterwards to solve little problems. That session helped us to understand what the main problems had been on the Sunday.
"I have won many times in France and think it's a good track for both me and the Yamaha M1.
"Last year in fact I got a victory in the wet by a great distance over the rest. I rode a perfect race, without making a single mistake and in terrible track conditions."
After Honda's pair of one-twos, Marquez and Pedrosa are now first and second in the championship, with Lorenzo four points down in third and his Yamaha team-mate Valentino Rossi a further 14 adrift.