Combine honey, 1 cup sugar, and water in a saucepan; bring to a simmer and cook 5 minutes. Stir in lemon juice; bring to a boil and cook for 2 minutes. Remove from heat and let cool while you prepare the cake.

Preheat the oven to 350 degrees F (175 degrees C). Grease and flour a 9-inch square baking pan.

Combine flour, baking powder, orange zest, cinnamon, and salt in a bowl; set aside.

Beat remaining 3/4 cup sugar and butter together in a large bowl until light and fluffy. Beat in eggs, one at a time. Beat in flour mixture, alternating with milk, beating just until incorporated; stir in walnuts. Pour batter into the prepared pan.

Bake in the preheated oven until a toothpick inserted into center comes out clean, about 40 minutes.

Remove cake from oven and poke holes over the surface with a toothpick. Slowly ladle the cooled honey syrup over cake. For best results, set cake aside for 4 to 6 hours to cool and absorb the syrup before slicing and serving.