Some people say that it is very rare. Truth be told this is NOT true. It is rare but not very rare. I have truly seen this a lot in my area. So, don't listen to the people who say it is very rare because they are lying (or they are blind).
BTW, while i was writing this answer i saw 3 cloud to cloud lightnings.
Yes, lightning can occur above clouds. A type of lightning called "cloud-to-cloud" or "anvil crawler" lightning can be seen branching out above storm clouds. This is typically caused by the electrical discharge between different regions within the cloud or between different clouds.
Cloud lighting
There are three main types of lightning strikes: cloud-to-ground strikes, intra-cloud strikes, and cloud-to-cloud strikes. Cloud-to-ground strikes are the most common and well-known type, where lightning extends from the cloud to the ground. Intra-cloud strikes occur within the cloud itself, and cloud-to-cloud strikes happen between different clouds.
This is called a cumulonimbus cloud.
"ball lightning"
Cloud-to-cloud lightning is commonly referred to as intracloud lightning because it occurs entirely within the same cloud without reaching the ground.
It's called in-cloud or cloud-to-cloud lightning.
It's called in-cloud or cloud-to-cloud lightning.
It's called in-cloud or cloud-to-cloud lightning.
It's called in-cloud or cloud-to-cloud lightning.
Sky lightning is more commonly known as a lightning bolt or simply lightning.
When lightning strikes within one cloud, it is called intra-cloud lightning. This type of lightning occurs when electrical charges within the same cloud become imbalanced, leading to a discharge between different areas of the cloud. Intra-cloud lightning is the most common form of lightning, often appearing as flickering flashes of light.
Double ZapperYes. In fact, visible lightning usually comes up from the ground into the cloud! The lightning bolt is actually retracing a path of weak electricity that the cloud sent down as a sort of "feeler" sensing for the shortest path to take to the ground. So if you're in an open space during a lightning storm, and you feel your hair stand up from static electricity, you might want to run for cover!
When lightning strikes within one cloud, it is called intra-cloud lightning. This type of lightning occurs when the electric charge within a cloud becomes unbalanced and discharges within the same cloud, rather than traveling to the ground or to another cloud.
The cloud sends down electrons to the ground and when it finds a substance lightning can travel through than a discharge travels up to the cloud, the lightning. If you stand on rubber lightning wont discharge.
Lightning is just really large static. Lightning between clouds is called cloud lightning or sheet lightning and is caused when one cloud has an excessive charge and another cloud has an excessive amount of the opposite cloud. The lightning is used to relieve the clouds charge.
There are many types of lightning STREAMERS that start a lightning strike. There are 3 basic places where streamers will originate from. They can come from a cloud to the ground or the ground to a cloud or from cloud to cloud. So your teacher was correct. But not always from the ground.