I can't find any reference to it but I am almost sure that I read somewhere that Lotus and Renault were working together on an aluminium tub platform design. Anyone else recall that?
They worked together with Caterham (which was supposed to spawn its own version of the car, possibly more extreme than the Alpine) but then they started disputing on the direction of the project and split up two or three years ago

BTW: as a Lotus owner myself, I don't see this car as a direct competitor to my Elise. I think of it as a purer and more driver focussed alternative to a Cayman. This Alpine is going to be extremely more usable and comfortable then an Elise will ever be.