The Mighty Thor # 358 1985 VF+

The Mighty Thor # 358 published in August 1985 and written and drawn by Walt Simonson, features a story titled "When Dalliance Was in Flower!" which focuses on Lorelei's plot to make Thor fall in love with her and install Loki as king of Asgard. 

• Lorelei's Potion: At Loki's behest, Lorelei uses a love potion to bring Thor under her spell. Her goal is to convince the love-struck Thor that Loki should be the rightful ruler of Asgard.
• Beta Ray Bill on Earth: Meanwhile, on Earth, Beta Ray Bill and Sif encounter the Green Liberation Front (GLF) who are attempting to rob the Federal Reserve Bank. The GLF members are revealed to be working for the Soviet villain the Titanium Man, who is using them as pawns.
• The Trap Unravels: Sergei, one of the GLF members, realizes he's been duped and turns on the Titanium Man, causing the villain to teleport away.
• Heimdall's Intervention: Back in Asgard, just as Lorelei goes to inform Loki of her successful enchantment of Thor, a counter-spell by Heimdall (or another spell left by the Enchantress) takes effect, causing Lorelei to fall madly in love with Loki instead.
• Thor's Decision: Unaware of the twist in the plot, Heimdall informs a still-enchanted Thor that Malekith the Accursed has escaped, to which Thor responds with a bewitched decision to support Loki for king. 

The issue sets up a humorous and complicated scenario in Asgard that continues into the next issue, where Thor discovers the pair together, temporarily breaking the spell through sheer rage.