Great1, your remark is funny.... are we to presume that attorneys are not interested in morality?
The answer to your question is, it depends on the jurisdiction. Without being long-winded, courts in different states have concluded different things. Also, the Rules of Professional Conduct also vary from state to state. Some states stand firm that the attorney-client privilege as well as the ethical obligation of confidentiality protects against compelling an attorney to dicslose the whereabouts of his fugitive client. Other states have determined that such whereabouts is neither privileged nor confidential.... in which case the attorney would be compelled to disclosed or risk being held in contempt of court.
So the first thing you should do is aquaint yourself with the rules of professional conduct and the case law in your jurisdiction. It's a no brainer if your state protects the information. But if you're in a state that does not, once you learn of your client's whereabouts, first advise him to turn himself in (and when he says no), then advise him that if you are asked whether you know the client's location, you will be compelled to disclose it to the authorities.
Either way you slice it, the attorney is not harmed. And always keep in mind, your client, whether a fugitive or otherwise, always has a RIGHT to an attorney.