Final answer:
Jon Lord contributed to rock music by advocating for the fusion of classical and rock elements, thus enriching the genre with complexity and elegance.
Step-by-step explanation:
Jon Lord proposed the artistic idea of a fusion of classical and rock elements in rock music. This innovative approach was aimed at blending the robust, energetic sounds of rock with the intricate and sophisticated arrangements found in classical music. Lord, known for being a pioneer in integrating these two distinct genres, helped to create a hybrid style that expanded the boundaries and depth of rock music.