Torreira, who cost Arsenal a reported £27million, featured in all of Uruguay's World Cup games and started the quarter-final defeat at the hands of France.
"He is a young player already with good experience, but who wants to keep on growing".
Guendouzi emerged as a box-to-box midfielder at Lorient but excelled in a deeper role last season and he's already represented France at Under-20 level so he has a huge future ahead of him.
Mesut Ozil played a role in Lucas Torreira's move to Arsenal after he vacated the number 11 shirt to allow the Uruguay global to take it, according to a report in England.
Guendouzi recently emerged as a shock transfer target with the Mirror reporting over the weekend that Arsenal had agreed a £7m deal with Lorient to sign the young midfielder.More news: Umtiti scores only goal in win vs
"I feel very happy", he said.
The Greece global who has been heavily linked with the Premier League side since new manager Unai Emery took over has finally penned a deal. I want to become part of the club's history and to achieve great things here. I hope I can do great things here.
He has been handed the number 11 shirt for the 2018/19 campaign and will join up with the squad in early August.
"I tried to enjoy the World Cup as much as I could".