Lorenzo deeply thought about linking with Vladimir. Yes, he would help him, but finding his daughter will make him indebted. In their business, having a debt over someone went deeper than just gratitude.
That was why he didn't like being indebted to anyone, especially not the blonde who saved him.
He has been secretly going through Vladimir's files over the last months, looking for a link to his missing daughter. That had to be his last resort since someone more powerful was protecting Luca.
The plan was, to find Luca and through him get to the powerful person protecting him. That wouldn't be an easy task. With the table almost gone, he needed an alliance and Vladimir was the only trusted one.