The Gunners have splashed out £46 million on Lacazette, who will be expected to lead the line, while Alexis Sanchez is yet to leave Emirates Stadium despite intense speculation suggesting that he will be sold after entering the final 12 months of his contract.
Giroud could, therefore, find himself nudged further down the pecking order – having struggled for starts in 2016-17 – but Garde claims the two France internationals could be used in tandem by Arsene Wenger.
A man who spent three years working with Lacazette between 2011 and 2014 told France Football: "Olivier and Alexandre are two different players that Arsene needs.
"The seasons are long and the aims are high for a club like Arsenal. To have these two players at his disposal is not too much, and it is possible to put them both in the same XI.
"The proof, at Lyon, is that Alex and [former Lyon and Swansea striker] Bafe [Gomis] played alongside each other at Lyon with me. We got the balance right by playing a diamond midfield.
“That is something that Arsene could do with these two players. Alex is a player who is sufficiently intelligent to adapt to that, Olivier Giroud too."
Goal, though, reported on Friday that the Hammers are already considering looking elsewhere after being informed that the 30-year-old intends to stay put.
Giroud has also hinted at ignoring the ongoing rumours by stating a desire to challenge for more major honours with the Gunners.
Lacazette has been brought in to aid that trophy quest and his compatriot Francis Coquelin has billed him as a “goalscoring machine” as he prepares to open a new chapter in his career.
The Gunners midfielder told Arsenal Player: “I’ve known him for a very long time. We played together for the youth national team so I know him very well. I’m really happy he’s come to the club. He’s a real asset and a goalscoring machine.
“He scored 37 goals in all competitions last season, so he’s shown that he’s a very, very good goalscorer. I think he’s the fourth all-time leading goalscorer for Lyon, after scoring about 130 goals for the club. I’m really happy to have him in the team.
“He can do pretty much everything because he’s someone who likes to get on the ball too. He likes to run in behind the defences, that’s something he’s good at and, like I said, he’s a goalscorer.
“Even in Europe, it’s very difficult to find someone who can score 25 or 30 goals. If he can do that, it will be very special for the club and for the team.
“I’ve never seen someone coming on and scoring so many goals. I’ve seen him come on and score a hat-trick in 20 minutes. He shows that he doesn’t joke in front of the goal, he does the business and that’s what we need.”