Gossip-philes in the D.C. area might want to head over to LUX Lounge tonight for a potential celebrity sighting. L.A. DJ slash Lindsay Lohan girlfriend Samantha Ronson is guest DJing at the Mt. Vernon Triangle club tonight, and it’s possible the queen of rehab herself will be in tow—she’s often spotted hanging around Ronson’s gigs guzzling Red Bull and grooving to her gf’s beats. We’re kind of surprised to see Sam and Lindsay back in…