Now the chill has arrived, it’s all about wrapping up in style and an on-trend skirt is essential for your winter wardrobe. Leather skirts have made a huge impact on the catwalk, and are perfect for toughening up girlier pieces. Elegant yet edgy, leather was seen on every AW 2012 runway from Lanvin to Mulberry (above middle) and the A-list are hot on the trend, with Diane Kruger (above left) and Olivia Palermo (above right) sporting leather skirts at New York Fashion Week last month. While Diane let her Calvin Klein, black mini do the talking, Olivia went bohemian in a tan, mid-length skirt, paired with a cream shirt. Channel Diane…