Lukaku has been a massive success at the Hawthorns after arriving last summer.
The 19-year-old Belgium international has netted 12 goals this season and has admitted he would be open to the idea of extending his spell at the club.
Clarke would be delighted to keep Lukaku but stressed the matter would not be broached until the end of the season.
"If Chelsea want to leave him out for another season somewhere, I think we would have a strong chance of getting him back here, but it is a discussion for the summer," admitted Clarke.
"Chelsea are his parent club, he is their player and they will decide what they want to do first and foremost.
"Then, after that, hopefully we will get a chance to put ourselves in the hat."