Lenticular clouds are not always cumulus.
They are normally orographic, created by air being forced upwards due to a raised land mass, but you can get lenticular cumulus, usually Alto Cumulus, Strato Cumulus or cirrocumulus.
Cumulus can be created orographically too.
Cumulus clouds are normally created through convection, created by small thermals, over warm pockets of land or the sea.
The more energy, the quicker & larger the cumulus cloud forms.
I checked before posting, Royal Meteorological Society & the Met Office, not wanting to look like a total plank.
