Lohan lived at the Hollywood Hills mansion with Ronson until they broke up this month.
X17online.com photographers said Lohan appeared "calm ... happy" when she visited Ronson this week.
Usmagazine.com said Ronson also changed her relationship status on Facebook from "Single" to "It's complicated" the same day as the meeting.
Lohan said on "The Ellen DeGeneres Show" this week she still loved Ronson and hoped they could work things out. She also revealed they "are talking."