When is the -s pronounced at the end of "plus"?

Although "plus" is spelled the same whether the -s is pronounced or not, they are two different words.When the -s is pronounced, it means more. Eg: "Je veux plus de chats" means "I want more cats".When the -s is not pronounced, it is a negative adverb which means no more or not any more. It must be used in coordination with "ne". Eg: "Je ne veux plus de chats" means "I do not want anymore cats".