After many, many tries, many of them very, very close indeed, I finally defeated Flame Lurker in NG+.
Man, he sure gets harder from one playthrough to the next.
He was on me alllllll the time, rarely got any breathing space, and he had none of the movement / finding me issues I exploited in my first game.
SL 152. all stats between 30 and 32 except for Faith and Luck (20 each), and Endurance (40), full Binded armour set, Moon Winged Spear +4, Purple Flame Shield +9, Talisman of Beasts, and the Warding spell.
Cast warding before entering the Boss fog.
Cast one homing soul arrow as he runs toward me, usually takes off about a 1/3 of his health with 30 magic.
Keep shield up constantly, strafe / roll until he misses me with an attack, get in a few pokes, roll back, heal / recast warding if necessary, repeat.
Still not as easy as it sounds, though, took me about 16 attempts, wherein I experiment with all sorts of weapon / armour / spell combos before settling back to my most used one (mentioned above) and having patience and calmness for the battle.
Worked fine for me!
Good to have out of the way.