Playing over the minor iv chord in a major key presents a unique challenge. While simply arpeggiating each chord can outline the harmony effectively, it often shifts the focus away from melodic expression. I prefer to approach this change by emphasizing the notes that distinguish the iv chord from the I chord, allowing those differences to naturally convey the subtle tension and resolution.
Your melody should never sound like you are solving a problem to accurately playing against these two contrasting chords. Instead, your melody, should sound elegant and organic in spite of the contrast.
