After expressing deep unhappiness with Bridgestone's 2014 rubber during last week's Sepang test, Lorenzo has found the tyres far more to his liking in warmer conditions at the Australian track.
The focus of the test is on addressing the tyre wear issues that disrupted both the MotoGP and Moto2 races at Phillip Island last October, with suppliers Bridgestone and Dunlop assessing a wide variety of options during the three days of running.
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Yamaha rider Lorenzo got down to a 1m29.133s lap on Tuesday, two tenths of a second ahead of Honda rival Dani Pedrosa.
Ducati's Andrea Dovizioso completed the top three, with his team-mate Cal Crutchlow fifth behind the second Yamaha of Valentino Rossi.
The intention for Tuesday had been to run race simulations, but due to the very hot weather no one did more than a 14-lap run.
Only the current factory teams, minus the injured Marc Marquez, are taking part in the tyre test, with the rest of the field running in Qatar later this week instead.
Marc VDS's Tito Rabat was quickest of the Moto2 quartet present. Fellow Moto2 man Nico Terol caused the only accident-prompted red flag of the day when he fell at MG, although there was another stoppage when a flock of geese had to be removed from the track.
The test concludes on Wednesday, although the current forecast suggests rain will spoil day three.
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