The moves paid off, with Ramsey equalizing in the 83rd minute and Giroud sending the Emirates crowd home ecstatic with a goal two minutes later to give Arsenal a lead that they would not give up, earning the Gunners three points and a short-lived stint at the top of the table before the rest of the league kicks off this weekend.
Wenger said he had given the former Montpellier man the chance to leave but is delighted he opted to stay put.
The Gunners had won just one of their last seven opening-day fixtures and looked destined to start another campaign slowly as the 2015/16 champions took the lead twice, only to lose 4-3 at the Emirates Stadium.
"He had a scan two days ago and he's out for a while - I don't know if it two weeks or one more week, but he will not be available".
On Sanchez and Ozil's final year of contract, Wenger said: "When a player goes into the final year of their contract we will try to extend the contract because there is no reason we shouldn't do it, but we are not there yet".
It may just be me getting the wrong idea, but when I hear him talk about an exceptional player I instantly think of a creative or attacking one.
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"He is really loved here, we love him and, in the end, he made a decision to stay".
"I feel that the goals we conceded, we can work to get rid of that", he said.
There was still plenty to do, but somehow Lacazette found the pace and the direction to plant a header into the bottom corner, with not even two minutes showing up yet on the clock. It's no doubt going to spoil all of us because the rest of the games are going to suck by comparison.
An admiring Wenger said Giroud was "in his prime" and "at the top of his game".
Lacazette almost had his second of the night just minutes later, but Leicester keeper Kasper Schmeichel turned the shot aside, but Giroud beat the Dane with an exquisite header on the ensuing corner to give Arsenal the 4-3 victory.
Danny Welbeck then brought Arsenal back level on the brink of half-time. "We have plenty of the same type of player". "We were a threat and played football and contributed to a thoroughly entertaining game".