Simply asking the officer if having a lawyer will help, or simply saying the word lawyer is not enough. You must tell the officer "I want my attorney, I do not wish to speak with you until I have contact with my attorney." Once you say that, the officer (If you are under arrest or not) should stop interrogating you until your lawyer is reached.
Repeat That You will Not Talk Until Your Lawyer is Present
It is important that you stand by your statement. Do not simply ask for a lawyer and then continue to answer their questions. Remain calm and silent, and simply repeat you will not speak to them until you have spoken to your lawyer. Don't be convinced by the fact that the officer tells you that if you talk now they will drop the charges, chances are that is not the case. Simply refuse to speak until you have talked to an attorney.