There is a big difference between promotion and description. An encyclopedia should describe a subject objectively and neutrally. If it promotes an idea, it becomes an advertising tool, which Wikipedia shouldn't be. Describing consists of recounting facts. Promoting involves making subjective judgements about the facts and encouraging behavior. To include facts is not promotion, although doing so while leaving out other contradictory facts is biased, and can be considered promotional. So, the correct way to deal with pseudoscience (or any other article for that matter) is to describe the relevant, verifiable facts about the subject, whether positive or negative. 
As for Lerner being notable, he could be considered notable on two separate subjects, his cosmology work and his fusion work. His cosmology work received more attention in the 90s, but he is still active in it today, and has received some media attention. His fusion work is more recent, and has received some media attention as listed in the references.