The France international striker had been heavily linked with a move away from the Ligue 1 outfit during the transfer window, with Premier League side Newcastle United strongly tipped with his signature.
However, Lyon managed to keep hold of one of their most valuable assets with no deal being completed before Monday's deadline.
Aulas has now stated that Lacazette has signed a new deal, reportedly through to 2018, while also revealing that midfielder Yoann Gourcuff - who has struggled for form and fitness since joining in 2010 - has agreed to play this season on reduced terms.
"Yoann Gourcuff has agreed to reduce his salary for the season and we have extended the contract of Alexandre Lacazette by two years," Aulas said at a news conference.
Lacazette has started the new season well with three goals in four Ligue 1 matches.
However, the team have not replicated that form and have won once and lost three league games.