I get the instinct to give Klopp lots/all of the credit, but he's been good for longer than Klopp's been here. I think his game has taken another step up since Klopp arrived, but I honestly think the biggest thing Klopp has done to improve Lovren, aside from DL being a natural fit for Klopp's style, is dropping Skrtel. For one, Skrtel's just an abomination of a CB, so Lovren doesn't have to play alongside that, but it also allows him to play on the right, next to Clyne. That's just a tremendously solid right side of a back 4. Clyne is rarely caught out of position (unlike Moreno) and it allows Lovren to concentrate on the things he excels at and avoid the areas where he's weaker.