Honda had headed straight to Aragon while most of the teams stayed on at last weekend's race venue Barcelona for a test on Monday.
Heavy rain on Tuesday spoilt Honda's first day, but conditions improved for Wednesday.
Lorenzo's benchmark 1:48.076s lap came during a qualifying simulation, and pleased the world champion as he has often struggled at the Spanish track.
The Hondas of Marc Marquez and Dani Pedrosa were next up, with Valentino Rossi an encouraged fourth having made set-up breakthroughs.
Pedrosa did nine laps on Honda's 2014 bike during the day, but decided not to race it yet, despite the team's willingness to bring its debut forward if requested.
Marquez will remain at Aragon to try the machine on Thursday.
Satellite Honda riders Stefan Bradl and Alvaro Bautista completed the top six.
Randy de Puniet was 1.8 seconds off Lorenzo's pace on the Suzuki test bike.