Lemon cake has no flavor
The 'lemony' flavour in a lemon cake is from the volatile oils which are present in the fruit's zest,(mainly nerol, limonene and citral). I would'nt advise adding actual lemon juice to the cake as it will disrupt the ratios in the cake recipe and ususally the tart, zingy flavour gets lost anyway after baking. To get a really lemony flavour whilst still using a pound cake recipe (using the creaming method) there are several things which would enhance the lemon flavour:


Adding finely grated lemon zest to the sugar, then blitzing  with a blender (to release the oils) and leaving to infuse. The sugar is simply a medium to infuse into
Melting the butter (using it as a 'quasi' solvent) and adding it to some more lemon zest to infuse. Then once cooled use it as per the recipe requires.
Add lemon extract too (we're trying to get as much flavour as possible into the cake!)


And if all else fails, you can always soak the cake in a lovely tangy lemon syrup and may be top it off with some lemony cream cheese frosting!