Can someone give me some insight on the process to buy tickets to the Louvre & then purchase tickets for the 90 minute guided tour. Can we buy the tour tickets before we enter the Louvre ?

they have it here: https://www.ticketlouvre.fr/louvre/b2c/index.cfm/home

Yes, thank you. I hate to be obtuse but I'm still not clear if we buy tour tickets before we enter or do we buy them inside at the time of the tour.

You can literally buy them now on line. It allows you to pick the day and time and pay securely online. It also allows you to buy a general ticket (required in addition to tour) and the tour in your basket at the same time. Seems to be around 29 euro total.

The only delay at the Louvre is the security line to get in. You could easily buy your tickets once you finally get inside.

Last fall the security line for ticket holders was shorter than the non-holder security line, at least when we went there.

Don't forget: the Louvre is closed Tuesdays and it has evening hours Wednesday and Friday. It opens at 9 a.m., and we have found the best times, for smaller crowds, are first thing in the morning or in the evening. As with everything popular, things have changed. Our first Louvre visit, October 2000, the Louvre staff went on strike, but they kept the place open. And, it was all free. We recall having the place virtually to ourselves, maybe a few dozen patrons and a couple management employees for minimal security in some halls.

If going to several museums look into the Paris MuseumPass that allows unlimited entries to nearly all museumthat charge in Paris and Versailles too and gives priority entrance by skipping ticket lines I believe.

Paris Museum Pass | Official Website

Buy it at any participating museum - includes things like Pantheon and Conciergerie too.