Baptism

A fellow pastor had made mention in passing that the book of Acts contains examples of people being saved with out being baptized. Curious, when I checked it out all I could find were general descriptions such as:

17: 12 "Many of the Jews believed, as did also a number of prominent Greek women and many Greek men."

14:1 "There they spoke so effectively that a great number of Jews and Gentiles believed."

However _every_ conversion of an individual is _always_ accompanied by a baptism.

• Acts 1 "John's Baptism" v. "Spirit's Baptism"
  
• Acts 2 The Crowd at Pentecost
  
• Acts 8 Simon the Sorcerer
  
• Acts 8 The Ethiopian Eunuch
  
• Acts 9 (& Acts 22) Saul
  
• Acts 10 Cornelius
  
• Acts 16 Lydia
  
• Acts 16 Philippian Jailer & Family
  
• Acts 18 Crispus
  
• Acts 19 Apollos
  
• Acts 19 The Disciples of Ephesus

Even if I have overlooked something (which is likely) the overwhelming evidence seems to point toward baptism being the normal apostolic practice. 

Question: If the evidence from the book of Acts points toward baptism being a normative first response to the converting work of the Holy Spirit, what the Biblical grounds for conversion and baptism to be separated, as is our normative practice today?

Something to chew on.