The striker is currently with Hertha Berlin, which are prepared to sell this summer.
Lampard is eager to bring Kalou back to England, having spent six years together at Stamford Bridge, reports BILD.
Two months ago, Kalou said: "I had options to go somewhere else again. But where I feel good, like in Berlin, I want to stay there."
However, Hertha are now seeking to sell, despite the Ivorian, 32, being tied until 2020.