I would recommend around 40 or more atk, 40 or more str and OSRS gold 33 def or more before meleeing it. Maging it'll be awful as I read tht it has impressive magic def. At the stated melee lvls, u wud need a rune scimmy (40atk needed), and complete adamant armour (30 def needed), an amulet of str, and a str potion would help. . U also require the anti aging drag sheild, as without it, elvarg can hit upto 500 dmg.
Also, get a full inventory of lobsters/swordfish. Swordfish is a lot better, but killed elvarg at around 40-50 combat, using just 3-5 lobbies. This setup is merely for the last boss battle against elvarg the dragon btw. Yet another thing, having 33 magic may save 10k gp (such as telegrabing a map bit instead of buying it from the goblin). Also remember, u need 33 pursuit points to even begin this exploration. If u wish to, don't hesitate to contact me in game (Tarun Dragon) and I would be happy to help u, and finance u, if ur not good on cash. The entire quest costs around 50k, to 60k. After I did this, rune scimmies at which 60k by itself, so it cost me much more.
Everyone else has given you the very best information, except for two things. I believe an amulet of electricity would be a lot better than strength, as it boosts you precision and defence. A short sword will beat a scimitar against dragons, that are weak to stab strikes. I wanted to mention this also, although I forgot he'd need the extra atk at his lvl, and yeah, dragons are rlly feeble to stab (was attempting to think of an f2p stab wep, but cudn't lol).
If u do use a rune sword be certain to cheap RS gold have it set to a stab atk btw. Its still slower and weaker than a scimmy, on the plus side, u might strike more often, and its cheaper. But don't, u rllly don't need prayer to kill elvarg.
