A lazy Cattleya schilleriana

[Intruder]

Since more than 10 years I cultivated a Cattleya Schilleriana which flowered only once and it still badly left for the next year. I believe it should emit a new PB in Autumn but until now it produces only roots. The plant is beautiful and in good health.
I give him a maximum of light but that becomes more and more difficult because we advance in the season. I water it lightly two times per week and it receives no fertiliser. What can I do to make it leave its torpor?
Many thanks in advance for your help.