An arbitration clause which makes the effectiveness of the submission of the dispute to arbitrators conditional upon a prior and specific agreement between the parties, providing for the jurisdiction of the ordinary court in the absence thereof, constitutes a condition precedent the non-fulfilment of which results in the retention of state jurisdiction. It follows that, in the absence of proof that the parties have reached an agreement to refer the dispute to arbitrators, the objection to the jurisdiction of the ordinary court in favour of the arbitrator, raised pursuant to Article 819-ter of the Code of Civil Procedure, must be dismissed.