Romero finished at 13-under-par 275.
Weather delays Saturday forced many players, including Romero, to complete their third round early Sunday. Romero birdied his last two holes of the round and carded a 65 before heading on to the final 18 holes.
"I am very happy to win my first event on the PGA Tour," Romero said.
Lonard closed with a 3-under-par 69, finishing at 12-under 276. Tim Wilkinson was third, another stroke back, after a final-found 67.
Woody Austin needed a birdie on the last hole to force a playoff but drove into the left rough and then landed in water next to the green, ending up with a double-bogey.
Susan Sarandon 'very excited' about daughter's pregnancy
Senate Democrats to pull all-nighter on climate change