If there is a shada (the w looking thing) on a letter after alif lam, it get's skipped, otherwise, the connection is to the lam if preceded by a different word. If there is no word preceding, the alif makes a sound, but if there is a shada on the letter after lam, it skips the lam, otherwise, the lam gets included in the sound.
This is the Arabic equivalent of saying 'an apple' instead of 'a apple' if I remember correctly. For example, you say ar-rahman instead of al rahman. Is that corrrect?