Bucklin has a whole seminar lecture on when a client relationship starts, and the dangers to attorneys in not recognizing that they may be held to an attorney/client relationship even without agreeing to it.

But here is a short discussion on the subject.

"Traditionally, it has been said that the lawyer-client relationship begins when the client acknowledges the lawyer's capacity to act in his behalf and the lawyer agrees to act for the benefit and under the control of the client." ABA/BNA Lawyers' Manual On Professional Conduct, at 31:101 (2002) ("ABA/BNA Manual"). The existence of an attorney-client relationship is a fact question, necessarily dependent on the particular circumstances of the case. Moen v. Thomas, 2001 ND 110,  628 N.W.2d 325. An attorney-client relationship may be implied from the conduct of the parties. Storman v. Weiss, 65 N.W.2d 475, 520 (N.D. 1954). "[I]t may arise when a putative client reasonably believes that a particular lawyer is representing him and the lawyer does not disabuse the individual of this belief." ABA/BNA Manual, at 31:101. See also Moen, at ¶ 15. The existence of the relationship does not depend on an express contract or the payment of fees. Moen, at ¶ 13. See also, Disciplinary Board v. McKechnie, 2003 ND 22, www.court.state.nd.us/court/opinions/20020194.htm In short, if the prospective client can reasonably believe the prospective attorney is giving him/her legal advice, or will be doing so, there may be an implied attorney/client relationship.