If F35 use its radar, no need to be stealthy. And without radar use F35 is far from beiing IR discreet....
One min, are you saying that F-35 will be using its LPI radar and it will be detected, and rafale will never use its Radar? Take a situaiton, F-35 and Rafale are flying on oppositie sides. F-35 is flying with its Radar on, it detects the Rafale on its Radar, it aims with its AMRAAM and fires them The Rafale is not using its Radar, and since it does not have longer range missiles, its just trying to close down the range, so that it can fire using its missiles OR it can just disengage. F35 wll use its radar to guide its missiles to the Rafale, ... boom .. there goes the Rafale.
On other hand, Rafale disengages and saves its butt.
Now one thing I shall inform you, when both planes are on not using their radars, both will be dificult to detect, But F-35 has the advantage of range 1200 modules of APG-81 vs abt less than 1000 modules of RBE-2AA.
AMRAAM missile vs MICA (as you said before that France is buying Meteor for its customer and not for itself)
Thus how can the F-35 with longer ranged Radar and longer range missile be defeated by Rafale?
The only way it can do is only if it gets BVR but then if F-35 shuts its radar and goes about its business, how can Rafale detect it?