Monthly rotating roster that maintains order - php

Question

Background
I have a script which is used to rotate employees to share an allotment of car parks. Everything works fine i.e. i am able to retrieve a list of employees from a mysql db into an array, sort alphabetically and fill a table in a rotating fasion. All good.
What I am trying to achieve
What I would like to able to do is if I change the month i.e. from August to September the rotation from the current month will continue from where it left over in the previous month. Right now with the current script it will rotate perfectly within the given month but if i enter a new month the rotation is reset.
I have been thinking long and hard as to how i can carry over the rotation but struggling to figure this out.
Personal thoughts..
One thought maybe is should I flag in the mysqldb the last person in the rotation then in the next month continue the rotation beginning from the person who was flagged?
Here is the current working script
<?php
$weeks = array();
$month = 'Aug';
$year = '2015';
$date = new DateTime("first Monday of $month $year");
$thisMonth = $date->format('m');
while ($date->format('m') === $thisMonth) {
array_push($weeks, $date->format('d-m-Y'));
$date->modify('next Monday');
}
//print_r($weeks);
$weeks_count = count($weeks);
//echo $weeks_count;
//=========================================
include_once 'connect.php';
dbconnect("roster");
$NoOfRows = 8;
$NoOfWeeks = $weeks_count;
$totalLots = $NoOfRows * $NoOfWeeks;
$dataArr = array();
//fetch all persons
$query = "SELECT * FROM carpark ORDER BY First_Name";
$result = mysqli_query($conn, $query) or die("error getting data");
while ($row = mysqli_fetch_array($result, MYSQLI_ASSOC)) {
array_push($dataArr, $row['First_Name']);
}
$noOfPersons = count($dataArr);
//Create a new array with filling all lots
while ($noOfPersons < $totalLots) {
$dataArr = array_merge($dataArr, $dataArr);
$noOfPersons = count($dataArr);
}
$weekArr = array_chunk($dataArr , $NoOfRows);
//print the table
echo "<table border=1>";
for ($row = 0; $row < $NoOfRows; $row++) {
if ($row == 0) {
echo "<tr><th></th>";
for ($col = 1; $col <= $NoOfWeeks; $col++) {
$weeks_loop = $col-1;
echo "<th>Week $col<br>$weeks[$weeks_loop]</th>";
}
echo "</tr>";
}
for ($col = 0; $col < $NoOfWeeks; $col++) {
if ($col == 0) {
echo "<tr><td><strong>Bay $row</strong></td>";
}
echo "<td>";
echo $weekArr[$col][$row];
echo "</td>";
}
echo "</tr>";
}
echo "</table>";
?>
Screenshot of output
What should happen is if i change the next month, the rotation should start with Claire, Duncan, Gabriel and so on..