Complex sentence: First working with graphite pencil, Pitseolak would later move on to coloured pencil and felt-tip pens, which, according to Lalonde, became her favored medium because their "rich and vibrant colours" best expressed "the joyfulness that characterizes her work".
Split into simpler sentences: First working with graphite pencil, Pitseolak would later move on to coloured pencil and felt-tip pens. Lalonde said these became her favored medium because their "rich and vibrant colours" best expressed "the joyfulness that characterizes her work".