(a) A court before which an action is brought in a matter that is the subject of an arbitration agreement shall, if a party so requests not later than when submitting his or her first statement on the substance of the dispute, refer the parties to arbitration unless it finds that the agreement is null and void, inoperative, or incapable of being performed.
     (b) When an action referred to in subsection (a) of this Section has been brought, arbitral proceedings may nevertheless be commenced or continued, and an award may be made, while the issue is pending before the court.