On 13 May 2013, St-Denis was elected councillor for the Argenteuil Liberal Association's executive committee. Provincial riding associations represent the Provincial Liberal Party and participate in the general decision-making by sending delegates to varied conventions and congresses. On 6 October 2013, at the liberal nomination convention held at the Lachute Golf Club, St-Denis was elected as the official candidate for the Quebec Liberal Party to represent Argenteuil in the next election . At that time, Argenteuil was represented by Parti québécois member of the National Assembly, Roland Richer, elected during the partial election of 2012. At the dissolution of the National Assembly, on 5 March 2014, the Argenteuil Liberal Association offices on Main Street, Lachute, became St-Denis' official campaign headquarters. On 30 March 2014, less than seven days before the election, St-Denis held a liberal gathering at the Lachute Golf Club, with
Philippe Couillard and
Lise Thériault as invited guest speakers. Up to 800 partisans participated. On 7 April 2014, at the provincial general election, St-Denis won the riding of Argenteuil with 38.25% of the vote, thus returning Argenteuil under the Quebec Liberal Party banner. St-Denis' riding office in Lachute was formerly occupied by
David Whissell, and
Roland Richer. ==References==