PlanetJune patterns all work equally well for left- and right-handed crocheters – the only difference is that the finished result will be a mirror-image, depending on which hand you hold your hook in. Most patterns are symmetrical, so this rarely makes a difference, but, if you crocheted a dog who has a coloured patch over his right eye in the pattern (for example), your lefty-crocheted dog would just have the patch over his left eye instead.
In general, to convert a pattern to left-handed, the only things a lefty should switch are the words left and right and the words clockwise and counter-clockwise (UK: anti-clockwise). But PlanetJune patterns are lefty-friendly: I always specify any left-handed differences within the pattern, so you don’t need to worry about making any changes.
All PlanetJune crochet tutorials have left- and right-handed versions, and any special techniques in my individual patterns are also shown with left- and right-handed photos, for clarity 🙂