Thank you Jan for your perfectly comprehensible and very precise explanation. I note once again that between what is written in books and reality there are serious distances.
The only reference that I have is the Chadwick's book of (The classic cattleyas). They write:
"In United States, Catt lueddemanniana begins growing during the winter,and as soon the new growth is mature, it sends up buds and flowers in March and April with no rest period."
I don't know what is said about this subject in the Withmer's book.
After what I have observed these last days,you will easily understand my astonishment !
I have to add that it just comes to arrive on a French forum a presentation of a Cattleya lueddemanniana coerulea in flowers also.
Here
Remark: I already have changed the identification tab of the plant and I made it irrevocably!
Thank you for your help.