When clearly written and expressed, a provision in a written contract to settle by arbitration a controversy thereafter arising out of such contract, or out of the refusal to perform the whole or any part thereof, or an agreement in writing between two (2) or more persons to submit to arbitration any controversy existing between them at the time of the agreement to submit shall be valid, irrevocable, and enforceable, save upon such grounds as exist at law or in equity for the revocation of any contract; provided, however, that the provisions of this chapter shall not apply to collective contracts between employers and employees, or between employers and associations of employees, in respect to terms or conditions of employment; and provided further, that in all contracts of primary insurance, wherein the provision for arbitration is not placed immediately before the testimonium clause or the signature of the parties, the arbitration procedure may be enforced at the option of the insured, and in the event the insured exercises the option to arbitrate, then the provisions of this chapter shall apply and be the exclusive remedy available to the insured.