We class elective procedures as surgery that is scheduled in advance because it does not involve a medical emergency. The answer to your question will be different depending on the particular circumstances.
If you answer Yes to the Medical history question, are you on a waiting list for treatment? a small number of insurance providers will offer quotes for this situation and it should be declared on your policy. Please be sure to contact your insurance provider, to confirm what is actually included in your cover for the procedure as this will vary.
There are circumstances where elective surgery would not be covered on your policy. If the procedure is not as a result of a disease, illness or injury (i.e not a pre-existing medical condition) that would not be covered. An example of that might be cosmetic surgery. However, if you are awaiting cosmetic surgery which is required as a result of a pre-existing condition, some insurance providers may offer cover, please contact them to discuss this.
If you are travelling abroad to have medical treatment, including for cosmetic surgery cover is generally excluded from policies for that.