Russia’s capture of the strategic city of Lysychansk means the front line in Ukraine’s east will shift as Russian forces regroup before pushing further south and west, military analysts and Ukrainian officers said Sunday, ensuring that the next phase of the battle will be just as bloody as the last. To take Lysychansk and its neighboring city of Sievierodonetsk, Russian forces moved in from the north, east and west and created a pocket of territory that became indefensible toward the end of June. Now those Russian forces are in a position to attempt a similar maneuver on other Ukrainian-held cities...