"He has a lovely cat."
Translation:Il a un joli chat.
According to google, you are generally correct but there are exceptions to the rule. Adjectives that have to do with beauty, age, goodness, size (BAGS) should go before the noun. This article gives a more thorough explanation if you want a better understanding: http://www.dummies.com/languages/french/how-to-place-of-french-adjectives-correctly/