When seeking information is sarcasm seen as a deliberate lie?
Sarcasm isn't a deliberate lie, because the intention isn't to lie or mislead, but it is wrong speech, because it has the capacity to hurt people.

Per Buddhism, unless a statement is true and beneficial, it is not right speech. And joy derived from the suffering of others isn't wholesome.

Ironically saying "You lied" to someone who is being obviously sarcastic can be seen as a kind of sarcasm itself, since it can be viewed as being affectedly sincere.


  The criteria for deciding what is worth saying
  
  [1] "In the case of words that the Tathagata knows to be unfactual, untrue, unbeneficial (or: not connected with the goal), unendearing &amp;
  disagreeable to others, he does not say them.
  
  [2] "In the case of words that the Tathagata knows to be factual,
  true, unbeneficial, unendearing &amp; disagreeable to others, he does not
  say them.
  
  [3] "In the case of words that the Tathagata knows to be factual,
  true, beneficial, but unendearing &amp; disagreeable to others, he has a
  sense of the proper time for saying them.
  
  [4] "In the case of words that the Tathagata knows to be unfactual,
  untrue, unbeneficial, but endearing &amp; agreeable to others, he does not
  say them.
  
  [5] "In the case of words that the Tathagata knows to be factual,
  true, unbeneficial, but endearing &amp; agreeable to others, he does not
  say them.
  
  [6] "In the case of words that the Tathagata knows to be factual,
  true, beneficial, and endearing &amp; agreeable to others, he has a sense
  of the proper time for saying them. Why is that? Because the Tathagata
  has sympathy for living beings."
  
  — MN 58
  http://www.accesstoinsight.org/ptf/dhamma/sacca/sacca4/samma-vaca/